Engine exhaust silencer



Nov. 3, 1959 w. MCDONALD ENGINE mus'r smuczn Filed Dec. 13. 1957 I N VEN TOR. Will/am McDonald ATTORNEYS United States Patent 2,911,055 ENGINE EXHAUST SILENCER William McDonald, Oakland, Calif. Application December 13, 1951, Serial No. 702,691 1 Claim. Cl. 181-67) This invention relates to a silencing device, andmore particularly to a silencing device for an internalcombustion engine. p

The object of the invention is to provide a silencer for use with engines such as vehicle engines, whereby the usual noise and back pressure will be eliminated or minimized during operation of the engine.

A still further object of the invention is to provide an engine silencer that includes a plurality of spaced apart baffle sections or baflle means, and wherein each of the baffle sections includes helical members. which are provided with blades that are arranged so that the spaces therebetween increase progressively;

A further object of the invention is to provide an engine silencer that is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent durin the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are used to designate like parts throughout the same.

Figure l is a sectional view taken through the engine silencer of the present invention.

Figure 2 is a sectional view taken on the line 2-2 of Figure 1.

Figure 3 is a sectional view taken on the line 3-3 of Figure l. V

Figure 4 is a sectional view taken on the line 4-4 of Figure 1. a

Figure 5 is a view similar to Figure l, but illustrating a modification.

Referring in detail to' the drawings, and more particularly to Figures 1 through 4 of the drawings, the numeral indicates a silencer which comprises a hollow housing 11, and the housing 11 includes a main cylindrical portion 12, and tapered end portions 13 which terminate in cylindrical sleeves 14. The sleeves 14 are provided with split portions 15 so as to facilitate attachment of the silencer to pipes or conduits in the usual manner.

Arranged in the housing 11 are first, second, and third bafile means 16, 17, and 18, and these baffles means are spaced apart from each other as shown in Figure 1.

As shown in Figure 1, the first baflle means 16 includes a'hollow core 19 which has a cylindrical formation and which is hollow, and the front end of the core 19 is rounded as at 20. The numeral 21 indicates a helical body member which is mounted on'the core 19 and secured thereto, and the body member 21 includes blade portions 22, 23, 24, and 25. The blade portions 22 through 25 are arranged so that the space therebetween increases progressively.

The second batlle means 17 includes a central core 26 which has its front end rounded as at 27, and mounted on the core 26 is a helical body member 28 which includes blades 29, 30, 31 and 32. The space between the blades 29 through 32 increases progressively from "ice front to rear, and the space between the blades 24 and 25 is equal in size to the space between the blades 29 and 30. As shown in Figure 1, the third baffle means 18 1ncludes a central core 33 which has a front rounded end portion 34, and the numeral 35 indicates a helical body member which is secured to the core 33. The body member 35 includes blades 36, 37, 38, 39 and 40, and the space between these blades increases progressively from front to rear. The space between the blades 36 and 37 is equal in size to the space between the blades 31 and 32. It is to be noted that there are more blades on the baflie means 18 than there are on the bafile means 16 Referring now to Figure 5 of the drawings, there is shown a modified silencer which is indicated generally by the numeral 41, and the silencer 41 includes a hollow housing 42 which has tapered end portions 43 that terminate in cylindrical sleeves 44, and the sleeves 44 are provided with split portions 45. Arranged in the housing 42 are first, second and third baffle means 46, 47 and 48, and these baflle means are arranged in spaced apart relation with respect to each other. The first baffle means 46 includes a central core 49v which has a helical body member 50 thereon, and the body member 50 includes blades 51, 52, 53, 54, and 55.

The second bafile means 47 includes a central core 62 which has a helical body member 56 thereon, and the body member 56 includes blades 57, 58, 59, 60 and 61.

The third or rearwardly disposed bafile means 48 includes a central core' 64 which has a front rounded end 63, and the numeral 65 indicates a helical body member which is provided with blades 66, 67, 68, 69 and 70.

From the foregoing, it is apparent that there has been provided an engine silencer whichwill effectively reduce noise that ordinarily results from operation of an in-- ternal combustion engine such 'as an engine on a vehicle, truck, bus or the like. The silencer 10 of Figures 1 through 4 includes the sleeves or end portions 14 which are split as at 15' so the silencer can be conveniently attached to pipes or conduits of a vehicle, and the silencer 10 further includes the tapered portions 13 and the housing 11. Arranged in the housing 11 are the first, second and third bafile means, 16, 17, and 18. These baffle means are spaced from each other and each includes a central core and a helical body member. The helical body members are arranged so that the blades thereof have the spaces therebetween progressively increasing in size and this provides a means whereby noise from the engine is effectively dissipated or eliminated. In the silencer 10, the bafile means 16 and 17 have the same number of blades, while the baflle means 18 has a greater number of blades than the baflle means 16 and 17.

Referring now to Figure 5, the modified silencer 41 functions in substantially the same manner as the silencer 10. However, the silencer 41 includes the three baflle means 46, 47, and 48 which all have the same number of blades. This is in contrast to the silencer 10 which has the rear baffie means provided with an increased number of blades.

In Figure 1 the exhaust gases are adapted to travel in the direction indicated by the arrows, and in Figure 5, the exhaust gases are also adapted to travel in a direction from left to right.

The following is given as an example of the dimensions of the silencer 10. The inlet and outlet 14 may be 2 inches in diameter, and the portion 12 may be 26 inches long, and the cores may be one inch in the tubing. The space between the blades 22 and 23 is 1 /2 inches, the space between the blades 23 and 24 is 1 /8 inches, and

Patented Nov. 3, 1959 the space between the blades 24 and 25 is 1% inches. The space between the blades 29 and 30 is 1% inches, between the blades 30 and 31 is 1% inches, and between blades 31 and 32 is 2 inches. A space of 2% inches may be provided between the baffie means 16 and 17, and between the baffle means 17 and 18. The space between the blades 36 and 37 is 2 inches, between blades 37 and 38 is 2% inches, between blades 38 and 39is 2% inches, and between blades 39 and 40 is 2% inches. The portion 12 may have a diameter of inches.

The parts can be made of any, suitable material and in diiferent shapes or sizes. The silencer is especially suitable for use on passenger cars and the body member 21 may have three spirals or blades and the body member 28 also has three spirals while the body body member 35 has four spirals. The opening in the first spiral equals the capacity of the exhaust pipe and increases by A3 of an inch on every turn and the next bank or blade startswhere the last turn leaves off and the front end of the cores are closed.

In the silencer 41, each baffle means may have the same number of blades, and the space between the baffle means 46, 47 and 48 increases progressively. For example, when a silencer" 41 is to be used for trucks, buses or the like, the main portion of the housing 42 may have an 8 inch inside diameter, and the cores may be made of 2 inch tubing. Each baffle 46 may consist of three banks of four turns or spirals each. The sleeves 44 may be 3 inches in diameter, and a 3 inch space may be left between adjacent bafile means. I The blades 51 and 52 may have a space of 2 /2 inches therebetween, and between blades 52 and 53 is 2% inches,

while between blades 53 and 54 is 2% inches, and between blades 54 and 55 is 2% inches. Also, between blades 57 and 58 is 2% inches, between blades 58 and 5 9 is 3 inches, between blades 59 and 60 is 3% inches, and between blades 60 and 61 is 3% inches.

, Between blades 66 and 67 is 3% inches, between blades 67 and 68 is 3% inches, between blades 68 and 69 is 3 /2 inches, and between blades 69 and 70 is 3% inches.

When using the silencer on diesel motors and trucks, the parts may be made correspondingly larger so that for example, the inlet and outlet may be 4 inches in diameter and the other parts are of similarly larger shape.

The silencers 10 and 11 are similar except that for the passenger car type 10, the first and second baffle means 16 and 17 have three spirals while the other battle means 18 has four spirals.

The silencer of the present invention will serve to eliminate exhaust gases without the usual back pressureand the gases will flow along through the spiral around the centraltube or core and into the chambers until they reach the outlet end.

The above description of the invention is for illustrative purposes only and it is understood that modifications may be made inthe construction within the scope and spirit of the following claim.

I claim:

In an engine silencer, a hollow housing including a main cylindrical portion, a first, second and third spaced apart baffle means arranged in the cylindrical portion of said housing, said first bafile means comprising a hollow cylindrical core, the front end of said core being roundedand being closed, a helical body member mounted on said core and said body member being arranged and constructed so that its pitch progressively increases from front to rear so that there is a progressively increasing size of space between the blades of the helical body member, said second baflie means including a hollow core of cylindrical formation, the front end of said core being rounded and closed, a helical body member on said last named core, and said body member being arranged so that its pitch progressively increases from front to rear whereby thereis a-progressively increasing amount of space between the blades of the last named helical body member, the space between thelast two blades of the first bafi le means being equal inv size to the space between the first two blades of the second baffle means, said third bafile means including a hollow core of cylindrical.

formation, the front end of said core being rounded and being closed, a helical body member mounted on said core and said body member being arranged so that its pitch increases progressively from front to rear whereby there is a progressively larger space between the blades of the body member, the space between the rear two blades of the second bafile means being equal in size to the space between the front two blades of the third baffle means, said first and second baflie means having the same number of blades, and said third battle means having a;

greater number of blades than said first and second baflie means, a tapered portion on each end of said main portion, each tapered portion terminating in a cylindrical sleeve, and said sleeves having slots therein.

References Cited in the file of this patent UNITED STATES PATENTS 

